The Catfish
New member
Thought I would post my experience with these codes. I use these forums often to research issues and hadn’t seen much in these codes.
Have less than 1k miles on my 2023 AT4 with 3.0 diesel. CEL came on and had On Star run diagnostics and got Code U0623. Description read:
“Vehicle network communication code. The network provides a communications link between systems inside the vehicle and when the network is disrupted a code can be set. If vehicle functionality is impacted please seek service soon.”
I needed to travel the next day for work so decided to go ahead and drive w the CEL on until I could get it to dealership - wasn’t noticing any issues.
The next day on my way out of town, my cruise control shut off and the vehicle went into “reduced acceleration mode”. On Star says there’s a new code (with the same description) of U137E. So I took it to the nearest dealership I could find on my route. They troubleshot it all day and eventually I left in a loaner to be on my way.
After 3 days they got it fixed and pointed to a shot coolant pump. Still not clear to me if it shorted out, fouled up or what. Allegedly these U codes are hard to trace the culprit and it took a day and half just to find out what was going on.
Hope this helps someone down the road, and I pray I’m done w CEL on my new (friggin expensive) truck!
Have less than 1k miles on my 2023 AT4 with 3.0 diesel. CEL came on and had On Star run diagnostics and got Code U0623. Description read:
“Vehicle network communication code. The network provides a communications link between systems inside the vehicle and when the network is disrupted a code can be set. If vehicle functionality is impacted please seek service soon.”
I needed to travel the next day for work so decided to go ahead and drive w the CEL on until I could get it to dealership - wasn’t noticing any issues.
The next day on my way out of town, my cruise control shut off and the vehicle went into “reduced acceleration mode”. On Star says there’s a new code (with the same description) of U137E. So I took it to the nearest dealership I could find on my route. They troubleshot it all day and eventually I left in a loaner to be on my way.
After 3 days they got it fixed and pointed to a shot coolant pump. Still not clear to me if it shorted out, fouled up or what. Allegedly these U codes are hard to trace the culprit and it took a day and half just to find out what was going on.
Hope this helps someone down the road, and I pray I’m done w CEL on my new (friggin expensive) truck!
